Radio frequency transceivers requiring wide frequency coverage or bandwidth along with high RF power levels encounter difficulties with bandwidth limitations of available power transistor amplifier technology. Higher power RF transistors are significantly more limited in bandwidth than are lower power RF transistors using available semiconductor technology.
One option to achieving simultaneous wide bandwidth and high power is to combine multiple RF transistor amplifiers having smaller bandwidths which are evenly spaced so as to cover the desired wide bandwidth with contiguous smaller bandwidth segments. A practical subset of this approach is the use of two amplifiers. One amplifier covers the lower half bandwidth and the other covers the higher half bandwidth to achieve full band coverage.
The primary limitation of such an approach is the requirement of high-power RF switches. These switches must select from one of two high-power RF energy signals and must be high-speed in order to support the frequency hopping rate of the transmission signal. The technology to perform this switching is currently limited to implementation with PIN semiconductor diodes (i.e. those diodes having a wide, undoped intrinsic semiconductor region between a P-type semiconductor and an N-type semiconductor region) to achieve the high-speed/high-power switching. Such diodes require high voltage bias and high-speed driver circuitry that adds considerable complexity and cost to the implementation. In addition, the switch contributes to a reduction in the transmitter power output due to resistive power dissipation.
Therefore, it would be desirable to provide a wideband RF amplifier capable of transceiving via multiple antenna elements having a simplified construction and enhanced power management capabilities.